Visual and aural determination of direction and distance of sound



L. WALKER VISUAL AND AURAL DETERMINATION'OF DIRECTION AND DISTANCE OFSGUND Filed Jan. 10 1918 2 Sha'cs-fSheet 1 May 6 1924.

W. L. WALKER VISUAL AND AURAL DETERMINATION OF DIRECTION AND DISTANCE OFSOUND Filed Jan. 10 1918 2 Sheets-Sheet 2 Zwv'rcfbor:

Patented May 6, H924.

natur sates iii WILLIAM L. WAm OF NEW YORK, N. Y ASSIGNGE T WAT; if 51'SIGBT & EQUIP- MEN! CORPORATION, 03' NEW YO, N. Y., A CORFQRATION @FDELAWA :"l

VISUAL AND AU DETERMINATION OF DIRECTIQN AND DISTANCE @2 SQUIYD.

Application filed January 10, 191a. Serial no. enact.

To all whom'z't may concern: Be it known that 1, WILLIAM L. WALKER, acitizen of the United States, and resident of New York, in the county ofNew York 5 and State of New York, have invented new and usefulImprovements in Visual and Aural Determination of Direction and Distanceof Sound, of which the following isa specification.

This invention relates to the detection of sound and to thedetermination of the location of a source of sound and more-particularlyto the detection and location of submarine sound emanations. Certainphases of the present disclosure are set forthin my prior applicationsSerial No. 161,179, filed April 11, 1917; Serial No. 176,299, filed June22, 1917; Serial No. 202,680, filed Nov. 19, 19.17, and Serial No.210,380, filed January 4, 1918, and I hereby-make reference to. theseapplication for a more complete disclosure of such phases of the presentdisclosure.

The principal objects of the present in- 2 vention are to detectvibratory waves of audible frequency and of a certain character to theexclusion of waves of sounds of different character and to. determinethe location of the source of the detected sound waves. The present.invention is more particularly concerned in determining the direction ofthe sourceof sound but the distance as well as the direction of thesource may be determined according to the resent invention. In thepresent case I pre erably employ means for excluding interfering soundsfrom the indicating mechanism of the detecting system, but inasmuch asno such interference is met with under some conditions of operation suchmeans is essential only in the more limited aspect of the invention.

Other objects of the invention will be apparent from the followingdescri tion and the accompanying drawings, in w ich,

Figure 1 is a diagrammatic view of one embodiment of my improved system;

Figure 1" is a diagram illustrating one manner of applying the system toa vessel;

Figure 1" is a dia ram illustrating another manner ofapp ying the systemto avessel;

Figure 2 is a diagram showing a modified form of the invention;

.ary win Figure 3 is a diagram showing a still further modification ofthe invention;

Figure 4 is a side elevation of an improved indicator, parts beingbroken away; and

Figure 5 is a transverse section of the indicator taken on line 5-5 ofFig. 4.

The particular embodiment of the invention illustrated in Fig. 1comprises a pair of sound detecting, or receivingv devices D and Ddisposed in s aced relationship, as Y for example on o poslte sides of avessel or other vehicle as lndicated in Fig. 1" or on the same side of avessel as indicated in Fig. 1 and indicating apparatus such as anoscillograph 4, a telephone receiver R, or a'milliammeter 5, which ispreferably 10- cated in the chart room or pilot house of the vessel whenthev system is installed on board avessel, together with certainapparatus connected in circuits leading from the detectors D and Dbeneath the surface of the water to the indica-tin apparatus. Each ofthe circuits leading rom the detectors to the indicators is separate anddistinct until the circuits reach the transformer T where the individualcircuits are connected.

differentially tovthe primary windings P and P of the transformer insuch manner as conjointliy to induce current in the seconding S, towhich the indicating 1nstruments may be directly connected.

Each of'the individual circuits leading from the respective detectors Dand D to the transformer T is comprised as follows;

The microphone 1 is mounted on an oscillatory lever arm 2 and isactuated by a sound-receiving diaphra exposed to the water outside thevesse or otherwise arranged to receive sound vibrations transmittedthrough the water or other medium,

the construction of the micro hone and method of actuation preferablying sumlar to that disclosed in my said application Serial No. 202,680.The receiver 1 is connected by conductors 6 to the input terminals of anaudion or thermionic tube 7, the output circuit 8 vof which isconnectedto the central terminals of a double-pole double-throw switch 9.- Theupper pair of end terminals of the switch 9 are connec to theelectromagnet 10 of a vibrator device such as disclosed in my saidapplication Serial No. 210,380.

The microphone 11 carried by the Vlbl'fl.

A 2 ti:

tor V is connected to the primary winding through the medium of adouble-pole double-throw switch 12. When the switches are arranged asshown in the drawing current variations produced by the receiver 1 aretransmitted to the audion 7 where they are amplified and rectified andtransmitted to the electromagnet 10. The vibrator V is actuated by theelectromagnet 10 and in turn actuates the microphone 11 to producecurrent variations in the primary winding P As explained in my saidapplication Serial No. 210,380, the vibrator V may be adjustedpredominantly to reproduce a sound of a particular character so thatwhen properly adjusted it transmits or reproduces the component of thesound reaching microphone 1 corresponding to the sound to be detected.For example, it it is desired to detect a particular sound from amiscellany of sounds the vibrator V is adjusted predominantly toreproduce the particular sound and this sound will then be transmittedto the primary winding P whereas the other sounds will not be reproducedby the vibrator V except to a relatively small extent. Moreover thedetectors 1) and D may be tuned to particular sounds by varying theweight of the lever arms; by varying the adjustable weights along thelever arms, by varying the thickness or stillness of the diaphragms, byemploying damping rings on the diaphragms, or in other suitable manner.

When the detectors D and D are connected to the primaries P and Prespectively and in the same manner, as illustrated in Fig. 1, and whenthe two circuits so connecting the detectors to the transformerprimaries are adjusted in like manner sounds, received by the detectorswill produce opposite eilects in the transformer inasmuch as the primarywindings P and P are wound in opposite directions as shown.

Thus if the detectors be mounted on a vessel as illustrated in Pig. 1and if the vessel be pointing directly toward the source of sound SS thedetectors will be affected in equal degree and the currents in theprimary windings P and P will just balance each other, whereas it thevessel be directed to one side of the source of sound one of thedetectors will be afiected to a greater degree than the other andconsequently heavier variations of current will be produced in theprimary winding connected to the detector which is afi'ected to agreater extent.

' The unbalanced current in the primary windings P and P will induce acurrent in the secondary S proportional to the difi'erence between thecurrents in the primary windings P and P. Thus, while the system so faras already explained will not indicate on which side of the vessel thesource or" sound is located, it will indicate when the neeaese vessel ispointing directly toward the source of sound. Obviously instead oflocating the detectors on the port and starboard sides or" the vessel atthe forward and aft ends thereof, they might both be placed on the sidesof the vessel near the bow and stern respectively as illustrated in Fig.1 so as to indicate when the vessel is squarely broadside of the sourceof sound.

In order to determine on which side of the vessel the source of sound islocated when the vessel is not pointing directly toward the source, 1preferably provide auxiliary indicating devices such as receivers 1% ormilliammeters 15. These auxiliaryvdevices may be operatively connectedto the detectors D and D in any suitable manner, but I preferablyconnect them to the the circuits leading from the detectors at pointsbeyond the audion 7 Thus, in Fig. 1, I have illustrated circuits 16 and16 connecting the receivers 14 and 14 to the output circuits 8 and 8 ofthe audions 7 and 7, switches 17 and 17 being provided to short-circuitthe auxiliary indicating devices when their use is not required. Themillia-mmeters 15 and 15 are preferably connected directly in the outputcircuits of the audions as illustrated.

Under certain conditions of operation it may be desirable to connect thedetectors either directly to the indicating mechanism or indirectly tothe indicating mechanism through the audions to the exclusion of thevibratory devices V and V. For example, if there are no interferingsounds 11npinging upon the detectors the vibratory devices V and V maybe eliminated from the circuits and when the sound reaching'thedetectors, which it is desired to transmit to the indicating mechanism,is of sufiicient' intensity the detectors may be connected directly tothe indicating mechanism instead of through the audions. In the systemillustrated in Fig. 1 the vibratory devices V and V may be cut out ofthe circuits by throwing the switches 12 and 12 from the outer sets ofcontacts to the inner sets of contacts and by throwing the switches 9and 9 down. The circuit from each detector to the transformer would thencomprise conductors 6, audion 7, conductors 8 and conductors 19. Toconnect the detectors directly to the primary windings of thetransformer T, the switches 9 and 9 are thrown down, the switches 12 and12 are thrown to their inner sets of contacts, and the switches 21 and21 are closed, so that the circuit from each detector to the transformerwill comprise conductors 6, conductors 8, switch 9, conductors 19,switch 12 and tlieconductors leading to the transformer. In the eventthat it is desired to cut out the audions 7 without cutting out thevibrators V and V, the switches 21 and 21 are closed so as toshort-circuit the audions, the switches 9 and 9 are thrown into upperposition, and the switches 12 and 12' are thrown to the outer contacts,in which event the circuit from each detector" 'to the transformercomprises conductors 6, conductors 8, switch 9 in its upper position,vibrator V and switch 12 in the outer position shown in Fig. 1.

The batteries 22 and 22 in the circuits 6 and 6 supply current to thereceivers 1 and 1, and when the audions are short circuited by switches21 and 21 the batteries 22 and 22 cooperate respectively with thebatteries 23 and 23 to produce positive potentials on the plate and gridelements of the audions whether the microphones be connected to thevibrators V and V respectively or directly to the primary windings ofthe transform-' ers through the switches 9 and 9 in their lowerpositions.

Instead of using a single microphone 1 with each' of the detectors aplurality of microphones may be employed either in series or in parallelas more fully set forth in my prior application, Serial No. 210,380.

In order to afford a further indication of the direction of the sourceof sound reaching the detectors a magnetic pointer may be associatedwith the transformer Tas illustrated at 24 in Fig. 1. The pointer 24 ispivotally mounted at 25 to swing in the plane of the transformer T sothat the free end of the pointer will move along a graduated scale 26disposed between the primary windings P and P. The normal position ofthe pointer 24 is that shown in Fig.1, namely, half way between the endsof the primary windings P and P. While any suitable means may beprovided normally to maintain the pointer in this position I preferablymount the transformer ixrj a vertical plane so that the pointer will beheld in normal position by gravity. When the primary windings P and Pare equally energized the strength of the poles of the two windings willbe equal and the pointer will be permitted to stand in normal position.However, if one of the windings is energized to a reater extent than theother the pointer will e pulled toward the winding which is energized toa greater degree. Owing to the fact that the entially woun the polesproduced at the lower end of the windings will be of like polarity andif the poles are of equal strength the attraction for the pointer 24will be equal, but as above stated when one of the windings is energizedtoa greater degree than the other the attraction upon the pointer by thelower poles of the respective windings will become unbalanced and theointer will swing to the right or left, therey indicating that onedetector is receiving a greater volume of sound than the other prlmarywindings are differ-- and that therefore the source of sound is notdirectly ahead of the vessel but to one side thereof. In order that thedirection of the pointer 24 shall b proportional to the angulardisplacement of the source of sound relatively to the longitudinal axisof the vessel the length of the pointer, the weight of the magnetic pole27 carried at the lower end of the pointer and the other factorsgoverning the deflection of the pointer must be accurately adjusted.

When using the oscillograph 4 the direction of the source of sound maybe accurately determined as follows: The oscillograph, which is of thewell-known form, has three indicating mirrors, two of which areconnected with the respective primary coil leads by means of theconductors 50 and 50, the transformers 51 and 51 and the conductors 52,and 52. Said transformers 51 and 51 are those commonly ,used withoscillographs and prevent the direct battery currents from affecting thereadings. The variations of the currents in the two primary windings Pand P will be exactly in phase when the vessel is directed toward thesource of sound and theoretically there will be no current generated inthe secondary winding S. However, when the vessel deviates from thedirection of the source of sound the variations of current in therespective primary windings are thrown out of phase owing to the factthat the distances. from the source of sound to the respective detectorsare different. The oscillograph will indicate the composite waveproduced by the vector sum of the component currents in the respectiveprimary windings and the phase difference between the currents in theprimary windings will be indicated by the displacements of theindividual current waves produced by the receiving devices and recordedby two of the mirrors of the oscillograph. The third mirror will recordthe composite wave produced by combining the separate current waves fromthe receiving devices through their resultant'inductiv effect in thesecondary winding of'the transformer. A comparison of the phase anglesbetween the three wave records so made will enable the direction of thesource of the waves to be determined and a comparison of theiramplitudes with amplitudes at known distances will indicateapproximately the distance from the receivers. This will be moreapparent in view of the diagram shown in Fig. 2 which will now bedescribed.

Two detectors D and D are disposed in spaced relationship as describedin'connec tion with Fig. 1 and are connected directly to di-fi'erentialprimary windings P and P of the transformer T, the secondary S of thetransformer being connected to a receiver R. If the source of sound belocated at point S S the detector D would be exposed to the sound waveemanated from the source to greater extent than would the detector Theprimary winding P would therefore be energized to a different extentthan would the primary winding P and the pointer 28 would indicate thedirection of the source of sound while the re ceiver it would merelyindicate that the source of sound is not symmetrically disposed withrespect to the two detectors. The distances from the source of sound tothe detectors D and D are indicated by the dash lines 29 and 30 and thedistance to the detector 1), is obviously greater than to the detector1),. For this reason the variations of current in the primary windingswould be out of phase and the degree of phase difference, as indicatedfor example by oscillographic apparatus, employed as described inconnection with Fig. 1 would indicate the angular degree of displacementof the source of sound from the center line 31 of the apparatus.

In Fig. 3 I have illustrated a simplified system comprising twodetectors D and D differentially connected to a receiver R throughcircuits 32 and 33 including batteries 34 and 35. By virtue of thedifferential windings on the receiver no appreciable sound would beproduced in the receiver by a source of sound located directly ahead ofthe detectors 1), and D However as the apparatus is swung to the rightor left the detectors D and D would be actuated in different degree andthe receiver litwould indicate this difference in degree. If whenswinging the apparatus to the left the intensity of sound produced bythe receiver R, decreases it would be understood that the source ofsound were to the left of the apparatus, whereas if the intensity ofsound produced by the receiver increased it would be understood that thesource of sound were to the right of the apparatus. While my improvedapparatus is particularly adapted to indicate the direction of a sourceof sound it is also adapted to indicate the approximate distance fromthe apparatus to the source of sound inasmuch as the intensity of soundreaching the detectors will be proportional to the distance.

Indications of the approximate distance can be obtained by noting theintensity of sound in the telephones 1a and 14: when the switches 17 and17' are open. Thus the operator is enabled, after some experience, toestimate the approximate distance by comparison of the intensity of thereceived sound with intensities previously obtained at known distances.

The current indicated by the milliammeters l5 and 15 will vary more orless in accordance with the intensities of the received signals and sowill also give an indication neeaeeo from which the approximate distancemay be estimated.

If one of the coils P or P be thrown out of circuit by opening one ofthe switches 12 or 12, depending on which detector D or D is more nearlyat right angle to the source of sound, the connected coil. will aloneinduce currents in the secondary coil S which will cause the ammeter 5,the receiver it or the oscillograph a, to give different indicationsdepending on the intensity and distance of the sound waves when comparedwith. known distances.

The improved form of indicating trans former illustrated in Figs. i and5 comprises an annular magnetic core 4:1 surrounded by primary andsecondary windings P, P and S as in Fig. 1, indicating mechanismincluding an A-shaped frame 42 and a pointer 43, and a supporting frameF. The windings P, P and S are insulated from the frame F by means ofinsulation members 44-, 45 and d6 and are symmetrically positioned withrespect to a vertical plane through line 5-5. The frame 42 and pointerd3 are fast to a shaft which is mounted on knife edges in the top offrame F. The pointer moves over a scale 47 secured on one side of frameF. At the lower ends of the legs of the frame 42 are mounted magneticpole pieces 48 and 19, the pole pieces being placed somewhat closertogether than the primary windings, P and P so that the windings tend topull the pole pieces away from the center line 55 when energized. Whenthe two primary windings are equally energized the pole pieces arepulled in equal degree and the pointer stands at the center of thescale. However, if one winding is energized a greater degree than theother the opposing forces become unbalanced and the pointer swings tothe right or left as will be understood from the preceding description.

ll claim:

1. Apparatus for determining the direction of sources of vibratoryenergy comprising, electrical receiving devices located at spacedreceiving stations adapted to produce variable electric urrents whichvary in accordance with the intensities of the received waves,thermionic tubes in circuit therewith, coils connected with said tubesfor producing magnetic fields whose intensities vary in accordance withsaid last-named currents, inductive means located within the fields ofsaid coils and adapted to have currents induced therein by .said fieldswhich are the result of the currentsin said coils, and means fordetermining the relative intensities of said induced currents.

2. Apparatus for determining the direction of sources of vibratoryenergy comprising, electrical receiving devices located at spacedreceiving stations adapted to produce r accordance with said last-namedcurrents, in-

"ductive means located within the fields of said coils and adapted tohave currents induced therein by said fields and which are the result ofthe currents in said coils, and visual indicating means connected withsaid inductive means for permitting comparisons of the respectivecurrents therein.

3. Apparatus for determining the direction of sources of vibratoryenergy comprising electrical receiving devices located at spacedreceiving stations adapted to produce variable electric currents whichvary in accordance with the intensities of the received waves,thermionic tubes in circuit therewith, coils connected with said tubesfor producing magnetic fields whose intensities vary in accordance withsaid last-named currents, inductive means located within the fields ofsaid coils and adapted to have currents induced therein which are theresultant of the combined effects of said coils, means for aurallydetermining the intensities of said currents in said inductive means,and visual indicating means for comparing the respective currents insaid coils.

4. Apparatus of the character described comprising electrical receivingdevices responsive to waves of audible frequency, a transformer, anindicator adapted to be operated bythe induced fields thereof, circuitsconnecting the receiving devices with differentially wound primary coilsof the transformer, and supplementary means in circuit with thereceivers and the trans-former for determining the directionand'distance of the source of sound received by the receiving devices. 7

5. In an apparatus of the kind described, the combination of a pluralityof electroresponsive wave receiving devices, a plurality of sources ofelectric current, each of said sources being associated with one of saidreceiving devices and controlled thereby independently of the other ofsaid receiving devices, a transformer having primary coils connectedindividually to said current sources the coils acting in opposition onthe magnetic circuit of the transformer, a secondary winding on saidtransformer, means connected with said secondary winding for aurallydetermining the eflects of the fields of the primary circuits and visualmeans for V comparing the respective currents of said primary circuitsfor indicating the direction of the source of waves received by saidreceiving devices.

6. In an apparatus of the kind described, the combinatmn of a pluralityof electro-responsive wave receiving devices, a plurality of sources ofelectric current, each of said sources being associated with one of saidreceiving devices and controlled thereby independently of the other ofsaid receiving devices, a transformer having primary coils connectedindividually to said current sources, the coils acting in opposition onthe magnetic circuit of the transformer, a secondary winding on saidtransformer, means connected with said secondary winding for determiningthe eflects, of the fields of the primary circuits and visual means forcomparing the respective currents of said primary circuits forindicating the direction of the source of waves received by saidreceiving devices.

7. lnan apparatus for determining thedi rection and distance of a sourceof sound, the combination of receivers of audible frequency waves,conductors connected therewith, whereby the received waves vary thecurrents therein in accordance with the distance and direction ofthesources thereof, an oscillogra'ph connected with said conductors, meanswhereby said oscillograph is controlled by said currents simultaneously,and

WILLIAM L. WALKER.

